@inproceedings{DRR-2005-BairdB,
	author        = "Henry S. Baird and Jon Louis Bentley",
	booktitle     = "{Proceedings of the 12th Conference on Document Recognition and Retrieval}",
	ee            = "http://www.imaging.org/store/epub.cfm?abstrid=32864",
	isbn          = "0-8194-5649-7",
	pages         = "191--196",
	publisher     = "{SPIE}",
	series        = "{SPIE Proceedings}",
	title         = "{Implicit CAPTCHAs}",
	volume        = 5676,
	year          = 2005,
}